Wireless telegraph-transmitter



f5.1! ROUND ANH W. T. UNCH/XM.' .f'HELESS .TELEGVAPH TRANSMITTER AUFLCATION FILED AUG 2G. lf'U- 1,354,495 Intcned Jun. l, 1921.

M f ,U51 fvwm/ww UNITED STATES PATENT OFFICE.

.HENRY JOSEPH ROUND, OF LONDON, AND WILLIAMv THEODORE DITCHAH, OF TWICKENHAI, ENGLAND, ASSIGNORS TO RADIO CORPORATION OF AHER- ICA, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

WIRELESS TELEGRAIH-TRANSHITTER.

Specification of Letters Patent.

Patented Jan. 4, 1921 Application led August 26, 1920. Serial No. 406,180.

T0 all Quim/n it may concern Be it known that we, HENRY JOSEPH ROUND and IVILLIAM THEoDoRE DrroHfiM, subjects of the King of Great Britain, residing at 9 llvoodberry Crescent, Muswell Hill, London, N.. and Kildary, Lebanon Park, Twickenham, Middlesex, England, respectively, have invented certain new and useful Improvements in Wireless Telegraph- Transmitters, of which the following is a specification accompanied by drawings.

In a wireless telegraph transmitter where current from an alternating source is rectified and then smoothed out by a condenser, the oscillator. whether valve or spark, is worked off this condenser as a source of direct current.

Owing to the high resistance ofthe rectifying valve or valves the potential across the condenser varies greatly with the variations of load and as this potential determines the signal strength in the case of al spark set, and both the wave-length and signal strength in the case of a valve set it is most desirable that this potential be kept constant.

According to this invention we accomplish this by simultaneously opening and closing the circuits supplying current to the condenser and from the condenser to the oscillator.

My invention is illustrated by the accompanying drawing.

' In Figure l, T is an alternating lcurrent transformer, which delivers high tension current which is rectified by a rectifying valve R. L is a blocking condenser of large capacity which smoothes out the current to the oscillator, which is not shown. K, K1,

are two arms of a key or switch so'arranged l that they open the circuits simultaneously whereby the potential of L remains constant. In some cases the two arms of the key are shunted by resistances A, A, so that the transmitter is kept feebl'y oscillating even when the key is open. The resistances are so adjusted that the potential of L remains constant.

M is a main by which alternating current is supplied to the transformer T.

In the modified arrangement shown yin Fig. 2, the arm K opens the circuit of the oscillator as before, but the arm K1 of the switch opens the main circuit M. Here again the arm K may be shunted by a resistance A and the arm K1 by a choke coil C, A and C' being so adjusted that the condenser L remains at constant potential.

Fig,` 3 y'shows an arrangement in which the opening and closing ""of the circuits on the two sides of th'e condenser L are affected by three-electrode valves V andV1 thehgrids of which are connected to the armatures of two relays C, C1, arranged in circuit with a key le, the opening and closing of which cause the energization of the relays whereby the grids of the two valves are simulta-` neously connected to corresponding ends of batteries B, B1 and are thereby made positive and negative with respect to the filaments whereb the circuits on the two sides of condenser are opened and closed.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is 1. In a wireless transmitter, the combination of .a condenser, means for supplying rectified current thereto, an oscillator connected to the condenser and means for simultaneously opening and 'closing circuits connecting said condenser with the oscillator and the current supply. p

2. In a wireless transmitter the combination of a source of alternating current, a rectifying valve, an oscillator, a condenser, a connection between the condenserV and one terminal of the valve, a second connection between the condenser and the oscillator and means for simultaneously opening each of said connections. p

3. In a wireless transmitter the combination of an oscillator, meansl for supplying rectified current thereto, a condenser connected in parallel to the oscillator and the source of current supply, switching means for simultaneously opening and closing the circuits connecting the condenser to said oscillator and said source of current supply and an impedance in shunt with each of said switching means adapted to maintain the condenser at a constant potential when the switching means is operated.

HENRY JOSEPH ROUND. WILLIAM Tux-:00uur DITCHAM. 

